1. Field of the Invention
The present invention relates to a platinum temperature sensor, and more particularly, it relates to a platinum temperature sensor employing a platinum resistance thermometer.
2. Description of the Prior Art
Platinum, being chemically stable and having high temperature dependency of electrical resistance, is employed as to a material for a temperature sensor. In a conventional platinum temperature sensor, a platinum wire is spirally wound on an insulator, or a platinum resistance pattern is formed as a thick or thin film on a single plate-type alumina substrate, as shown in U.S. Pat. No. 4,028,657, 4,050,052 or 3,781,749.
However, the winding type platinum temperature sensor is high in cost, its size cannot be sufficiently reduced, and high resistance values cannot be attained. In the platinum temperature sensor employing a single alumina substrate, on the other hand, the size must be increased in order to attain a high resistance value, and a high resistance value cannot be attained if the size is reduced.
U.S. Pat. No. 3,845,443 discloses a sensor which comprises a cylindrical body and a platinum resistance pattern provided on the surface of the body. In such a sensor, however, pattern formation is difficult since the platinum resistance pattern must be formed on a curved surface, whereby the pattern is restricted in variety.